Question

在做了一些连接和填充后，我有以下格式的表格

  name    session_id   status 
    abc         1          null       
    xyz         2          11          
    jack        2          10
    zuck        1          10 
    paul        1          10

我希望我的结果能够像这样分组

 session_id   name+status                   
    1            abc:-1, zuck:10, paul:10
    2            xyz:11, jack:11

所以我在sql中使用了MySql group_concat，如

    SELECT sr.avail_id AS id,sr.student_id, sa1.punctuality_status as associate_punctuality_status, IF(
                    (sa.punctuality_status IS NULL),
                    (group_concat(u.firstname, ' ', u.lastname, ':', '-1'), 
                    (group_concat(u.firstname, ' ', u.lastname, ':', sa.punctuality_status)
                    ),
                    sr.tutor_id AS associate_id, FROM_UNIXTIME( sr.timestart ) AS timestart,  
                    sr.session_id AS session_id, sr.type AS session_type, p.name AS program_name,
             m.name AS module_name, ms.name AS session_name, sr.status as session_status FROM mdl_session_requests AS sr 
        LEFT JOIN mdl_session_attendee AS sa ON ( sr.student_id = sa.user_id AND sr.session_id = sa.session_id )  
        LEFT JOIN mdl_session_attendee AS sa1 ON (sr.tutor_id=sa1.user_id and sr.session_id=sa1.session_id)  
        INNER JOIN mdl_module_session ms ON ms.id = sr.course_id    
        INNER JOIN mdl_module m ON m.id = ms.module_id   
        INNER JOIN mdl_program p ON p.id = m.program_id   
        INNER JOIN mdl_user u ON u.id = sr.student_id    
        WHERE sr.tutor_id =438 group by avail_id order by sr.timestart desc

error =“＃1064 - 您的SQL语法有错误;请查看与您的MySQL服务器版本对应的手册，以便在'AS associate_id，FROM_UNIXTIME（sr.timestart）AS timestart，sr附近使用正确的语法。 session_id AS'在第6行“

这个sql有问题吗？

Answer 1

SELECT 
     s.session_id AS id,
     group_concat(SEPARATOR ', ' CONCAT(u.firstname, ' ', u.lastname, ':',IF(s1.status IS NULL,'-1',s1.status))), sr.tutor_id

FROM [a table]
GROUP BY session_id

问题：

没有表格条款
parentesis哪里不匹配
GROUP_CONCAT可以在一个字段上完成，因此您需要先CONCAT()所有值。

Mysql group_concat问题

1 个答案: